wolpertinger

i built a robot powered by 2 servos SM-S4303R. Before i used a 9V battery for supplying the arduino and servos via the external power supply. all went well and as expected, only battery life was not that long.Today i changed to a 6 x 1.2V rechargable AA battery powerpack with 2500 mAh each.Now, connected to the external arduino supply it does not work, servos turn but in reverse direction and not as programmed. Connecting the usb and all is ok at once. i measured the powerpack output voltage as 8.4 V.btw all AA´s are freshly recharged.

The servo seems to be rated upto 6V only. It may be pulling excess current with that battery pack and becoming unstable. The 9V battery probably limited the current and thus reduced the loop gain of the servo. Could you run the Arduino and the servo from 4 cells (4.8V)?

[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

Are you saying you powered the servos from the Arduino's 5V regulator?Are these special low current servos?

"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.Do not send technical questions via personal messaging - they will be ignored.I speak for myself, not Arduino.

You shouldn't ever run servos from the Arduino's regulator; it is only rated at 500mA.(Another sticky thread candidate)

"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.Do not send technical questions via personal messaging - they will be ignored.I speak for myself, not Arduino.